1. Technical Field of the Invention
The present invention relates to a toner remain amount detecting method, an image forming apparatus and MFP, and particularly to a toner remain amount detecting method, an image forming apparatus and MFP that are capable of detecting the toner remain amount with higher accuracy.
2. Related Art
Conventionally, there are JP-A-10-20721 and JP-A-2003-149933 as known examples related to detection of a toner remain amount by estimation from a toner supply amount.
JP-A-10-20721 discloses an image forming apparatus and a toner remain amount detecting method in which, on the basis of a toner near-empty judgment value or a judgment value, an actual toner supply amount per supply is calculated from the count value of the number of times of toner supply up to a current point of time and the first toner filling amount from a toner cartridge, and then the toner supply amount per supply is modified to a prescribed value or the number of times of toner supply is modified while leaving the toner supply amount unchanged.
However, in the image forming apparatus disclosed in JP-A-10-20721, the toner supply amount per supply is calculated by determining near-empty state, and a sensor for detecting the toner remain amount must be prepared. Therefore, for example, in the case of a color image forming apparatus, a sensor must be provided in each developer and the apparatus becomes more expensive.
Meanwhile, JP-A-2003-149933 discloses an image forming apparatus having a counter that collects number-of-rotation information of a toner supply device which supplies toner to a developing device by rotation, a storage unit that saves the number-of-rotation information of the toner supply device, and a calculating unit that calculates a toner use amount or toner remain amount of the toner supply device on the basis of the number-of-rotation information saved in the storage unit, and a method of correcting the number of rotations of the toner supply device and thus calculating the toner use amount.
However, it is confirmed by the results of experiment that the correct toner remain amount cannot necessarily be detected even if the number of rotations is corrected on the basis of a toner supply mechanism including a toner cartridge supply port, a motor, a clutch and the like, or the toner remain amount in the cartridge at the time of supply, as in the image forming apparatus and the toner remain amount detecting method disclosed in JP-A-2003-149933.
Thus, a toner remain amount detecting method, an image forming apparatus and MFP that are capable of detecting the toner remain amount with higher accuracy are demanded.